Processes for the production of fluoropropanes and halopropenes

ABSTRACT

A process is disclosed for making CF 3 CH 2 CHF 2 , CF 3 CH═CHF, and/or CF 3 CH═CHCl. This process involves reacting at least one starting material selected from the group consisting of halopropenes of the formula CX 3 CH═CH 2  and halopropenes of the formula CX 2 ═CHCH 2 X, wherein each X is independently F or Cl, with HF and Cl 2  in a reaction zone to produce a product mixture comprising HF, HCl, CF 3 CH 2 CHF 2 , CF 3 CH═CHF and CF 3 CH═CHCl; and recovering the CF 3 CH 2 CHF 2 , CF 3 CH═CHF, and/or CF 3 CH═CHCl from the product mixture. The molar ratio of HF to the total amount of starting materials fed to the reaction zone is at least stoichiometric, and the molar ratio of Cl 2  to total amount of starting material fed to the reaction zone is 2:1 or less.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of application Ser. No. 12/444,462which represents a national filing under 35 U.S.C. 371 of InternationalApplication No. PCT/US2007/022995 filed Oct. 31, 2007, and claimspriority of U.S. Provisional Application No. 60/855,538 filed Oct. 31,2006.

FIELD OF THE INVENTION

The present invention relates to processes for the production of1,1,1,2,2-pentafluoropropane, 2,3,3,3-tetrafluoro-1-propene,1,1,1,3,3-pentafluoropropane, 1,3,3,3-tetrafluoro-1-propene,2-chloro-3,3,3-trifluoro-1-propene and/or1-chloro-3,3,3-trifluoro-1-propene.

BACKGROUND OF THE INVENTION

As a result of the Montreal Protocol phasing out ozone depletingchlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs),industry has been working for the past few decades to find replacementrefrigerants. The solution for most refrigerant producers has been thecommercialization of hydrofluorocarbon (HFC) refrigerants. The newhydrofluorocarbon refrigerants, HFC-134a being the most widely used atthis time, have zero ozone depletion potential and thus are not affectedby the current regulatory phase out as a result of the MontrealProtocol. The production of other hydrofluorocarbons for use inapplications such as solvents, blowing agents, cleaning agents, aerosolpropellants, heat transfer media, dielectrics, fire extinguishants andpower cycle working fluids has also been the subject of considerableinterest.

There is also considerable interest in developing new refrigerants withreduced global warming potential for the mobile air-conditioning market.

1,1,1,3,3-Pentafluoropropane (CF₃CH₂CHF₂ or HFC-245fa), a refrigerantand blowing agent, may be prepared by fluorination of1,1,1,3,3-pentachloropropane (CCl₃CH₂CHCl₂ or HCC-240fa) in the liquidphase (see for example, U.S. Pat. No. 6,291,730).

1,1,1,2,2-Pentapropane (CF₃CF₂CH₃ or HFC-245cb), useful as a refrigerantand blowing agent has been prepared by the addition of methyl fluorideto tetrafluoroethylene in the presence of antimony pentafluoride asdisclosed in U.S. Pat. No. 6,184,426.

2,3,3,3-Tetrafluoro-1-propene (CF₃CF═CH₂ or HFC-1234yf), useful as arefrigerant and as a polymer intermediate has been prepared byfluorination of CH₃CF₂CCl₃ over chromium oxide as disclosed by Rausch inU.S. Pat. No. 2,996,555.

1-Chloro-3,3,3-trifluoro-1-propene (CF₃CH═CHCl or HCFC-1233zd) is usefulas a chemical intermediate and may be prepared by fluorination ofHCC-240fa as disclosed in U.S. Pat. No. 6,013,846.

1,3,3,3-Tetrafluoro-1-propene (CF₃CH═CHF or HFC-1234ze) useful as arefrigerant has been prepared by dehydrofluorination of HFC-245fa usinga strong base in aqueous or alcoholic solution or by means ofchromium-containing catalyst in the presence of oxygen at elevatedtemperature as disclosed in U.S. Pat. No. 6,124,510, and fromHCFC-1233zd as disclosed in U.S. Pat. No. 5,895,825. HFC-1234ze has alsobeen prepared from HCC-240fa as disclosed in U.S. Pat. No. 6,111,150.

2-Chloro-3,3,3-trifluoro-1-propene (CF₃CCl═CH₂ or HCFC-1233xf) is usefulas an intermediate and as a monomer for polymers. HCFC-1233xf has beenprepared by dehydrochlorination of 1,2-dichloro-3,3,3-trifluoropropaneusing potassium hydroxide as described by Haszeldine in Journal of theChemical Society (1951) pages 2495 to 2504.

There is a need for processes for the manufacture of a compound from thegroup HCFC-1233xf, HFC-245fa, HFC-245cb, HFC-1234ze, HCFC-1233zd, andHFC-1234yf, where other compounds of the group are also produced fromcommon halogenated hydrocarbon starting materials and those othercompounds can, if desired, also be recovered.

SUMMARY OF THE INVENTION

The present invention provides a process for making at least one productcompound selected from the group consisting of CF₃CF₂CH₃, CF₃CF═CH₂ andCF₃CCl═CH₂. The process comprises reacting at least one startingmaterial selected from the group consisting of halopropanes of theformula CX₃CH₂CH₂X, halopropenes of the formula CX₃CH═CH₂, andhalopropenes of the formula CX₂═CHCH₂X wherein each X is independentlyselected from the group consisting of F and Cl, with HF and Cl₂ in areaction zone, optionally in the presence of a chlorofluorinationcatalyst, to produce a product mixture comprising HF, HCl, CF₃CF₂CH₃,CF₃CF═CH₂ and CF₃CCl═CH₂, wherein the molar ratio of HF to total amountof starting material fed to the reaction zone is at least stoichiometricand wherein the molar ratio of Cl₂ to total amount of starting materialfed to the reaction zone is 2:1 or less; and recovering said at leastone product compound from the product mixture.

The present invention also provides a process for making at least oneproduct compound selected from the group consisting of CF₃CH₂CHF₂,CF₃CH═CHF and CF₃CH═CHCl. The process comprises reacting at least onestarting material selected from the group consisting of halopropenes ofthe formula CX₃CH═CH₂ and halopropenes of the formula CX₂═CHCH₂X whereineach X is independently selected from the group consisting of F and Cl,with HF and Cl₂ in a reaction zone, optionally in the presence of achlorofluorination catalyst, to produce a product mixture comprising HF,HCl, CF₃CH₂CHF₂, CF₃CH═CHF and CF₃CH═CHCl, wherein the molar ratio of HFto total amount of starting material fed to the reaction zone is atleast stoichiometric and wherein the molar ratio of Cl₂ to total amountof starting material fed to the reaction zone is 2:1 or less; andrecovering said at least one product compound from the product mixture.

DETAILED DESCRIPTION

The term “starting material”, as used herein, means halopropanes orhalopropenes which react with hydrogen fluoride (HF) and chlorine (Cl₂)in a reaction zone in the embodiments of this invention. As indicatedabove, for certain processes of this invention the starting material isselected from the group consisting of halopropanes of the formulaCX₃CH₂CH₂X, halopropenes of the formula CX₃CH═CH₂ and halopropenes ofthe formula CX₂═CHCH₂X, wherein each X is independently selected fromthe group consisting of F and Cl; and for certain other processes ofthis invention the starting material is selected from the groupconsisting of halopropenes of the formula CX₃CH═CH₂ and halopropenes ofthe formula CX₂═CHCH₂X, wherein each X is independently selected fromthe group consisting of F and Cl.

The processes of this invention use a molar ratio of HF to the totalamount of starting material that is at least stoichiometric. Thestoichiometric ratio is determined by subtracting the weighted averageof the number of fluorine substituents in the starting material(s) fromthe weighted average of the number of fluorine substituents in thedesired product(s). For example, for producing a C₃H₃F₅ isomer fromC₃H₄Cl₄, the stoichiometric ratio of HF to C₃H₄Cl₄ is 5:1. As anotherexample, for producing a 1:1 mixture of HFC-245cb to HFC-1234yf fromCF₃CH═CH₂, the stoichiometric ratio of HF to CF₃CH═CH₂ is 1.5:1.

Certain compounds produced by the processes of this invention may existas one of two configurational isomers. For example, HFC-1234ze andHCFC-1233zd may each exist as E- or Z-isomers. As used herein HFC-1234zerefers to the isomers, E-HFC-1234ze or Z-HFC-1234ze, as well as anycombinations or mixtures of such isomers; and HCFC-1233zd as used hereinrefers to the isomers, E-HCFC-1233zd or Z-HCFC-1233zd, as well as anycombinations or mixtures of such isomers.

As indicated above, the present invention provides a process thatinvolves producing a product mixture comprising at least one productcompound selected from the group consisting of HFC-245cb, HFC-1234yf andHCFC-1233xf using at least one starting material selected from the groupconsisting of halopropanes of the formula CX₃CH₂CH₂X, halopropenes ofthe formula CX₃CH═CH₂ and halopropenes of the formula CX₂═CHCH₂X. Ofnote are embodiments of this process wherein HFC-1234yf is recovered.Additional HFC-1234yf may be obtained by dehydrofluorination ofHFC-245cb from the product mixture. Also of note are embodiments of thisprocess wherein HCFC-1233xf from the product mixture is fluorinated toproduce at least one of HFC-1234yf and HFC-245cb.

The product mixture may also comprise HFC-1234ze. The HFC-1234ze may berecovered. The product mixture may further comprise HCFC-1233zd.HFC-1234ze and HFC-245fa may also be obtained by fluorination ofHCFC-1233zd from the product mixture.

The product mixture may also comprise HFC-245fa. The HFC-245fa may berecovered. The HFC-245fa may also be dehydrofluorinated to produceHFC-1234ze.

The product mixture may further comprise HFC-1234ze. A mixture ofHFC-245cb and HFC-1234ze may be recovered and further reacted with HF inthe liquid phase under fluorination conditions in the presence of afluorination catalyst to produce a mixture comprising HFC-245fa andHFC-245cb. Alternatively, a mixture of HFC-245cb and HFC-1234ze may berecovered and further reacted under dehydrofluorination conditions inthe presence of a dehydrofluorination catalyst to produce a mixturecomprising HFC-1234ze and HFC-1234yf.

HFC-245fa, HFC-1234ze and/or HCFC-1233zd may also be present in theproduct mixture. HFC-245cb, HFC-1234yf, and HCFC-1233xf from the productmixture together with HFC-245fa (if present), HFC-1234ze (if present)and HCFC-1233zd (if present) may be further reacted with HF in theliquid phase under fluorination conditions in the presence of afluorination catalyst to produce a mixture comprising HFC-245fa andHFC-245cb. The HFC-245fa and HFC-245cb from the mixture may bedehydrofluorinated (individually or as a mixture) to produce bothHFC-1234ze and HFC-1234yf which may be recovered. See for example, U.S.Patent Application Publication US2006/0106263(A1), which is herebyincorporated herein by reference.

HCFC-1233zd and HFC-245fa may also be present in the product mixture;and HCFC-1233xf, HCFC-1233zd, and HFC-245fa from the product mixture maybe further reacted with HF in the liquid phase under fluorinationconditions in the presence of a fluorination catalyst to produce amixture comprising CF₃CH₂CHF₂ and CF₃CF₂CH₃.

As indicated above, the present invention also provides a process thatinvolves producing a product mixture comprising HFC-245fa, HFC-1234ze,and HCFC-1233zd using at least one starting material selected from thegroup consisting of halopropenes of the formula CX₃CH═CH₂ andhalopropenes of the formula CX₂═CHCH₂X. Of note are embodiments of theprocess wherein HFC-1234ze is recovered. Additional HFC-1234ze may beobtained by dehydrofluorination of HFC-245fa from the product mixture.Also of note are embodiments of this process wherein HCFC-1233zd fromthe product mixture is fluorinated to produce at least one of HFC-1234zeand HFC-245fa.

Also of note are processes wherein HFC-245fa is recovered.

Also of note are processes wherein the product mixture further comprisesHFC-1234yf and wherein HFC-1234yf from the product mixture is recovered.

The product mixture may further comprise HFC-245cb. A mixture ofHFC-245cb and HFC-1234ze may be recovered and further reacted with HF inthe liquid phase under fluorination conditions in the presence of afluorination catalyst to produce a mixture comprising HFC-245fa andHFC-245cb. Alternatively, a mixture of HFC-245cb and HFC-1234ze may berecovered and further reacted under dehydrofluorination conditions inthe presence of a dehydrofluorination catalyst to produce a mixturecomprising HFC-1234ze and HFC-1234yf.

HFC-245cb, HFC-1234yf and/or HCFC-1233xf may also be present in theproduct mixture. HFC-245fa, HFC-1234ze and HCFC-1233zd from the productmixture together with HFC-245cb (if present), HFC-1234yf (if present)and HCFC-1233xf (if present) may be further reacted with HF in theliquid phase under fluorination conditions in the presence of afluorination catalyst to produce a mixture comprising HFC-245fa andHFC-245cb. The HFC-245fa and HFC-245cb from the mixture may bedehydrofluorinated (individually or as a mixture) to produce bothHFC-1234ze and HFC-1234yf which may be recovered. See for example, U.S.Patent Application Publication US2006/0106263(A1).

HCFC-1233xf may also be present in the product mixture; and HCFC-1233xf,HCFC-1233zd, and HFC-245fa from the product mixture may be furtherreacted with HF in the liquid phase under fluorination conditions in thepresence of a fluorination catalyst to produce a mixture comprisingCF₃CH₂CHF₂ and CF₃CF₂CH₃.

Suitable halopropane starting materials of the formula CX₃CH₂CH₂Xinclude CF₃CH₂CH₂F (HFC-254fb), CF₃CH₂CH₂Cl (HCFC-253fb), CClF₂CH₂CH₂Cl(HCFC-252fc), CCl₂FCH₂CH₂Cl (HCFC-251fb) and CCl₃CH₂CH₂Cl (HCC-250fb).Preferred is HCC-250fb.

Suitable halopropene starting materials of the formula CX₃CH═CH₂ includeCF₃CH═CH₂ (HFC-1243zf), CClF₂CH═CH₂ (HCFC-1242zf), CCl₂FCH═CH₂(HCFC-1241zf), and CCl₃CH═CH₂ (HCC-1240zf). Preferred is HFC-1243zf.

Suitable halopropene starting materials of the formula CX₂═CHCH₂Xinclude CCl₂═CHCH₂Cl (HCC-1240za).

HCC-250fb is a readily available starting material that can be preparedby the reaction of ethylene with carbon tetrachloride as disclosed inInternational Patent Application No. WO 97/05089, which is incorporatedherein by reference. HCC-250fb may be converted to HFC-1243zf byreaction with HF in vapor phase as disclosed in U.S. Pat. No. 6,329,559,which is incorporated herein by reference. HCC-1240za may be prepared byreaction of 1,1,1,3-tetrachloropropane with ferric chloride as disclosedby Fujimori, et. al. in Japanese Kokai 49066613.

The reaction may be carried out in the liquid or vapor phase. For liquidphase embodiments of the invention, the reaction of starting materialswith HF and Cl₂ may be conducted in a liquid-phase reactor operating inbatch, semi-batch, semi-continuous, or continuous modes. In the batchmode, starting materials, Cl₂, and HF are combined in an autoclave orother suitable reaction vessel and heated to the desired temperature.

Preferably, this reaction is carried out in semi-batch mode by feedingCl₂ to a liquid-phase reactor containing HF and starting materials or byfeeding starting materials and Cl₂ to a liquid-phase reactor containingHF, or by feeding Cl₂ to a mixture containing HF and reaction productsformed by initially heating starting materials and HF. Alternatively, HFand Cl₂ may be fed to a liquid-phase reactor containing a mixture ofstarting materials and reaction products formed by reacting HF, Cl₂, andstarting materials. In another embodiment of the liquid-phase process,HF, Cl₂, and starting materials may be fed concurrently in the desiredstoichiometric ratio to the reactor containing a mixture of HF andreaction products formed by reacting HF, Cl₂, and starting materials.

Suitable temperatures for the reaction of HF and Cl₂ with startingmaterials in the liquid-phase reactor are from about 80° C. to about180° C., preferably from about 100° C. to about 150° C. Highertemperatures typically result in greater conversion of the startingmaterials.

A suitable molar ratio of HF to total amount of starting materials fedto the liquid-phase reactor is at least stoichiometric and is typicallyfrom about 5:1 to about 100:1. Of note are embodiments wherein the molarratio of HF to starting material is from about 8:1 to about 50:1. Asuitable molar ratio of Cl₂ to total amount of starting materials fed tothe liquid-phase reactor is from about 1:1 to about 2:1.

The reactor pressure in the liquid-phase process is not critical and inbatch reactions is usually the autogenous pressure of the system at thereaction temperature. The pressure of the system increases as hydrogenchloride is formed by replacement of hydrogen substituents by chlorine,and by replacement of chlorine substituents by fluorine in the startingmaterials and intermediate reaction products. In a continuous process itis possible to set the pressure of the reactor in such a way that thelower boiling products of the reaction, such as HCl, CF₃CF═CH₂,E/Z-CF₃CH═CHF, and CF₃CF₂CH₃, are vented from the reactor, optionallythrough a packed column or condenser. In this manner, higher boilingintermediates remain in the reactor and the volatile products areremoved. Typical reactor pressures are from about 20 psig (239 kPa) toabout 1,000 psig (6,994 kPa).

In embodiments of the invention in which the reaction is conducted usinga liquid-phase process, catalysts which may be used include carbon,AlF₃, BF₃, FeCl_(3-a)F_(a) (where a=0 to 3), FeX₃ supported on carbon,SbCl_(3-a)F_(a), AsF₃, MCl_(5-b)F_(b) (where b=0 to 5 and M=Sb, Nb, Ta,or Mo), and M′Cl_(4-c)F_(c) (where c=0 to 4, and M′═Sn, Ti, Zr, or Hf).Preferred catalysts for the liquid phase process are MCl_(5-b)F_(b)(where b=0 to 5 and M=Sb, Nb, or Ta).

Preferably, the reaction of HF and Cl₂ with starting materials iscarried out in the vapor phase. Typically a heated reactor is used. Anumber of reactor configurations are possible including horizontal orvertical orientation of the reactor as well as the sequence of reactionof the starting materials with HF and Cl₂. In one embodiment of theinvention, the starting materials may be initially vaporized and fed tothe reactor as gases.

In another embodiment of the invention, starting materials may becontacted with HF, optionally in the presence of Cl₂, in a pre-reactorprior to reaction in the vapor-phase reactor. The pre-reactor may beempty, but is preferably filled with a suitable packing such as Monel™or Hastelloy™ nickel alloy turnings or wool, or other material inert toHCl and HF which allows efficient mixing of starting materials and HFvapor.

Suitable temperatures for the pre-reactor for this embodiment of theinvention are from about 80° C. to about 250° C., preferably from about100° C. to about 200° C. Temperatures greater than about 100° C. resultin some conversion of the starting materials to compounds having ahigher degree of fluorination. Higher temperatures result in greaterconversion of the starting materials entering the reactor and a greaterdegree of fluorination in the converted compounds. Under theseconditions, for example, a mixture of HF, Cl₂, and HCC-250fb isconverted to a mixture containing predominantly HFC-1243zf and HCFC-243db (CF₃CHClCH₂Cl) and a mixture of HF, Cl₂, and HFC-1243zf is convertedto a mixture containing predominantly HCFC-243 db and HCFC-244 db(CF₃CHClCH₂F).

The degree of fluorination reflects the number of fluorine substituentsthat replace chlorine substituents in the starting materials and theirchlorinated products. For example, HCFC-253fb represents a higher degreeof fluorination than HCC-250fb and HFC-1243zf represents a higher degreeof fluorination than HCC-1240zf.

The molar ratio of HF to the total amount of starting material(s) in thepre-reactor is typically from about the stoichiometric ratio of HF tothe total amount of starting material to about 50:1. Preferably, themolar ratio of HF to the total amount of starting material in thepre-reactor is from about twice the stoichiometric ratio of HF to thetotal amount of starting material to about 30:1. In one embodiment ofthe invention, the preferred molar ratio of HF to the total amount ofstarting materials is present in the pre-reactor, and no additionalamount of HF is added to the vapor-phase reaction zone.

In another embodiment of the invention, the starting materials may becontacted with Cl₂ in a pre-reactor, optionally in the presence of HF,prior to reaction in the vapor-phase reactor.

Suitable temperatures for the pre-reactor for this embodiment of theinvention are from about 80° C. to about 250° C., preferably from about100° C. to about 200° C. Under these conditions, at least a portion ofCX₃CH₂CH₂X is converted to CX₃CHClCH₂X, at least a portion of CX₃CH═CH₂is converted to CX₃CHClCH₂Cl, and at least a portion of CX₂═CHCH₂X isconverted to CX₂ClCHClCH₂X. Higher temperatures typically result in ahigher degree of halogenation of the starting material.

The degree of halogenation reflects the total number of halogensubstituents (chlorine plus fluorine) in a halopropane and/orhalopropene product. For example, HFC-245cb has a higher degree ofhalogenation (i.e., 5) than does HCC-250fb (i.e., 4); and HFC-1234yf hasa higher degree of halogenation (i.e., 4) than does HFC-1243zf (i.e.,3). The preferred degree of halogenation in the halopropane products inthe process of this invention is five. The preferred degree ofhalogenation of halopropene products in the process of this invention isfour.

The molar ratio of Cl₂ to the total amount of the starting materials istypically from about 0.5:1 to about 2:1. Preferably the molar ratio ofCl₂ to the total amount of the starting materials is from about 1.1:1 toabout 1:1.

In a preferred embodiment of the invention, the starting materials arevaporized, optionally in the presence of HF, and fed to a pre-reactor orto a vapor-phase reactor along with HF and Cl₂.

Suitable temperatures for the vapor-phase reaction of this invention arefrom about 120° C. to about 500° C. Temperatures of from about 250° C.to about 350° C. favor the formation of HFC-1234yf and HFC-245cb.Temperatures of from about 350° C. to about 450° C. favor the formationof HFC-1234ze, HFC-245fa, and HCFC-1233zd. At temperatures of from about250° C. to about 450° C., some HCFC-1233xf is also produced. Highertemperatures result in greater conversion of starting materials andhigher degrees of fluorination and halogenation in the convertedcompounds.

Suitable reactor pressures for the vapor-phase reactor may be from about1 to about 30 atmospheres. A pressure of about 15 to about 25atmospheres may be advantageously employed to facilitate separation ofHCl from other reaction products, and the suitable reaction time mayvary from about 1 to about 120 seconds, preferably from about 5 to about60 seconds.

The molar ratio of HF to the total amount of starting material(s) forthe vapor-phase reaction is typically from about the stoichiometricratio of HF to the total amount of starting material to about 50:1 andpreferably from about 10:1 to about 30:1.

Preferably a catalyst is used in the reaction zone for the vapor-phasereaction of HF and Cl₂ with starting materials. Chlorofluorinationcatalysts which may be used in the vapor phase reaction of the inventioninclude carbon; graphite; alumina; fluorided alumina; aluminum fluoride;alumina supported on carbon; aluminum fluoride supported on carbon;fluorided alumina supported on carbon; magnesium fluoride supported onaluminum fluoride; metals (including elemental metals, metal oxides,metal halides, and/or other metal salts); metals supported on aluminumfluoride; metals supported on fluorided alumina; metals supported onalumina; and metals supported on carbon; mixtures of metals.

Suitable metals for use as catalysts (optionally supported on alumina,aluminum fluoride, fluorided alumina, or carbon) include chromium, iron,cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium,platinum, manganese, rhenium, scandium, yttrium, lanthanum, titanium,zirconium, and hafnium, copper, silver, gold, zinc, and/or metals havingan atomic number of 58 through 71 (i.e., the lanthanide metals).Preferably when used on a support, the total metal content of thecatalyst will be from about 0.1 to about 20 percent by weight based onthe total weight of the catalyst; typically from about 0.1 to about 10percent by weight based on the total weight of the catalyst.

Suitable chlorofluorination catalysts for the vapor-phase reactions inthis invention include chromium-containing catalysts includingchromium(III) oxide (Cr₂O₃); Cr₂O₃ with other metals such as magnesiumhalides or zinc halides supported on Cr₂O₃; chromium(III) halidessupported on carbon; mixtures of chromium and magnesium (includingelemental metals, metal oxides, metal halides, and/or other metal salts)optionally supported on graphite; and mixtures of chromium and othermetals (including elemental metals, metal oxides, metal halides, and/orother metal salts) optionally supported on graphite, alumina, oraluminum halides such as aluminum fluoride.

Chromium-containing catalysts are well known in the art. They may beprepared by either precipitation methods or impregnation methods asgenerally described by Satterfield on pages 87-112 in HeterogeneousCatalysis in Industrial Practice, 2^(nd) edition (McGraw-Hill, New York,1991).

Of note are chlorofluorination catalysts that comprise at least onechromium-containing component selected from the group consisting ofcrystalline alpha-chromium oxide where from about 0.05 atom % to about 6atom % of the chromium atoms in the alpha-chromium oxide lattice arereplaced by trivalent cobalt atoms, and crystalline alpha-chromium oxidewhere from about 0.05 atom % to about 6 atom % of the chromium atoms inthe alpha-chromium oxide lattice are replaced by trivalent cobalt atomswhich has been treated with a fluorinating agent. These catalysts,including their preparation, have been disclosed in U.S. PatentApplication Publication US2005/0228202 which is incorporated herein byreference in its entirety.

Optionally, the metal-containing catalysts described above can bepretreated with HF. This pretreatment can be accomplished, for example,by placing the metal-containing catalyst in a suitable container, andthereafter, passing HF over the metal-containing catalyst. In oneembodiment of this invention, such container can be the reactor used toperform the chlorofluorination reaction in this invention. Typically,the pretreatment time is from about 15 to about 300 minutes, and thepretreatment temperature is from about 200° C. to about 450° C.

In one embodiment of this invention, the product mixture comprisesHFC-245cb, HFC-245fa, HFC-1234yf, HFC-1234ze, HCFC-1233zd andHCFC-1233xf.

Halopropane by-products that may be formed in the chlorofluorinationreactions of this invention having higher degrees of halogenation and/orfluorination than pentafluoropropanes include CF₃CCl₂CF₃ (CFC-216aa),CF₃CClFCClF₂ (CFC-216ba), CF₃CClFCF₃ (CFC-217ba), CF₃CF₂CClF₂(CFC-217ca), CF₃CHFCF₃ (HFC-227ea), CF₃CF₂CHF₂ (HFC-227ca), CF₃CClFCHF₂(HCFC-226ba), CF₃CF₂CHClF (HCFC-226ca), CF₃CHClCF₃ (HCFC-226da),CF₃CCl₂CHF₂ (HCFC-225aa), CF₃CClFCHClF (HCFC-225ba), CF₃CF₂CHCl₂(HCFC-225ca), CF₃CCl₂CClF₂ (CFC-215aa), CF₃CClFCCl₂F (CFC-215bb),CF₃CCl₂CCl₂F (HCFC-214ab), CF₃CCl₂CHClF (HCFC-224aa), and CF₃CClFCHCl₂(HCFC-224ba).

Halopropene by-products that may be formed in the chlorofluorinationreactions of this invention having a higher degree of halogenation thantetrafluoropropenes include CF₃CCl═CHCl (HCFC-1223xd).

In cases where the product mixture produced by the processes of thisinvention comprises (i) product compounds HFC-245cb, HFC-245fa,HFC-1234yf, HFC-1234ze, HCFC-1233zd and HCFC-1233xf, (ii) HF, HCl, andCl₂, (iii) higher boiling by-products such as CF₃CHClCH₂C₁, CF₃CHClCH₂Fand (iv) chlorinated by-products such as C₃HCl₃F₄, C₃HCl₂F₅, C₃HClF₆,C₃Cl₃F₅, and C₃Cl₂F₆, the separation steps (a) through (e) may beemployed to recover the product compounds from such a product mixture.

In separation step (a), the product mixture may be delivered to adistillation column to separate HCl and Cl₂ from the product mixture.

In separation step (b), the product mixture from separation step (a) maybe delivered to one or more distillation columns to separate theazeotropic composition of HFC-1234yf and HF from the rest of the productmixture. The recovered azeotropic composition of HFC-1234yf and HF maybe further separated into individual components by using proceduressimilar to those described in U.S. Patent Application PublicationUS2006/0106263(A1).

In separation step (c), the product mixture from separation step (b) maybe delivered to one or more distillation columns in which HF, HFC-245cb,HFC-1234ze, HCFC-1233xf, HCFC-1233zd, and HFC-245fa are recovered fromthe top of the distillation column, and the higher boiling by-productssuch as CF₃CHClCH₂Cl, CF₃CHClCH₂F and the chlorinated by-products suchas C₃HCl₃F₄, C₃HCl₂F₅, C₃HClF₆, C₃Cl₃F₅, and C₃Cl₂F₆ are removed fromthe bottom of the distillation column. The higher boiling by-productssuch as CF₃CHClCH₂Cl and CF₃CHClCH₂F may be further separated from thechlorinated by-products, e.g. by distillation, and may be recycled backto the vapor-phase chlorofluorination reactor.

In separation step (d), the product mixture comprising HF, HFC-245cb,HFC-1234ze, HCFC-1233xf, HCFC-1233zd and HFC-245fa, which is recoveredfrom the top of the distillation column in separation step (c), may bedelivered to one or more distillation columns to recover the azeotropiccomposition of HFC-245cb/HF and the azeotropic composition ofHFC-1234ze/HF from the top of the distillation column. The recoveredHFC-245cb/HF and HFC-1234ze/HF azeotropic compositions may then befurther separated into individual components by using procedures similarto those described in U.S. Patent Application PublicationUS2006/0106263(A1).

In separation step (e), the product mixture comprising HCFC-1233xf,HCFC-1233zd and HFC-245fa and any HF recovered from the bottom of thedistillation column in separation step (d) may be delivered to adistillation column to separate the HCFC-1233xf, HCFC-1233zd andHFC-245fa. The HCFC-1233xf can be fluorinated to produce at least one ofHFC-245cb and HFC-1234yf. The HCFC-1233zd can be fluorinated to produceat least one of HFC-245fa and HFC-1234ze.

As indicated above, in certain embodiments of this invention, themixture of HF, HFC-245cb and HFC-1234ze, made according to the processof the invention is contacted with additional HF in a liquid-phasefluorination reactor, optionally in the presence of a liquid-phasefluorination catalyst to give a mixture of HF, HFC-245cb and HFC-245fa.The mixture of HF, HFC-245cb, and HFC-245fa is then separated into theindividual components by using procedures similar to those described inU.S. Patent Application Publication US2006/0106263(A1). Suitablefluorination catalysts for these embodiments may be selected from thosedescribed for the liquid-phase embodiment of the chlorofluorinationreactor described herein. The mole ratio of HF to HFC-245cb andHFC-1234ze in these embodiments is typically from about 5:1 to about100:1, and is preferably from about 10:1 to about 40:1 based on theamount of HFC-1234ze in the mixture. Suitable temperatures for theseembodiments of the invention are within the range of from about 30° C.to about 180° C., preferably from about 50° C. to about 150° C. Suitablereactor pressures for these embodiments are usually the autogenouspressures at the reactor temperatures. The pressure may be in the rangeof from about 1 to about 30 atmospheres.

As indicated above, in certain embodiments of this invention, a mixtureof HF, HFC-245cb and HFC-1234ze, made according to the processes of thisinvention, may be delivered to a reaction zone containing adehydrofluorination catalyst (optionally after removal of the HF).Conditions in the reaction zone are chosen to be suitable for conversionof HFC-245cb to HFC-1234yf. The products leaving the reactor, comprisingHFC-1234ze and HFC-1234yf are separated by techniques known to the art.Catalysts suitable for these embodiments of the invention and suitableoperating conditions are disclosed in U.S. Pat. No. 5,396,000 theteachings of which are herein incorporated by reference. Preferably, thedehydrofluorination catalyst comprises aluminum fluoride or fluoridedalumina or trivalent chromium oxide. Reaction temperatures suitable forthese embodiments are from about 150° C. to about 500° C. Contact timesin the reaction zone for these embodiments are typically from about 1second to about 500 seconds.

As indicated above, in certain embodiments of this invention, a mixtureof HCFC-1233xf, HCFC-1233zd, and HFC-245fa made according to the processof the invention, is reacted with HF in a liquid-phase fluorinationreactor in the presence of a liquid-phase fluorination catalyst to givea mixture of HF, HFC-245cb and HFC-245fa. The conditions of thefluorination are similar to those described for the mixture ofHFC-1234ze and HFC-245cb above. The mixture of HF, HFC-245cb, andHFC-245fa is then optionally delivered to a distillation column toseparate the two pentafluoropropanes and azeotropic HF by usingprocedures similar to those described in U.S. Patent ApplicationPublication US2006/0106263(A1).

As noted above, HFC-245cb, made according to the processes of thisinvention, may be dehydrofluorinated to produce HFC-1234yf, andHFC-245fa, made according to the processes of this invention, may bedehydrofluorinated to produce HFC-1234ze. Typical dehydrofluorinationreaction conditions and dehydrofluorination catalysts are disclosed inU.S. Pat. No. 5,396,000, which is herein incorporated by reference.Dehydrofluorination reaction temperatures suitable for this inventionare from about 150° C. to about 500° C.; however, higher temperature aredesirable for the dehydrofluorination of HFC-245cb. Suitable contacttimes for these dehydrofluorinations are from about 1 second to about500 seconds. Preferably, the dehydrofluorination catalyst comprises atleast one catalyst selected from the group consisting of aluminumfluoride, fluorided alumina, and trivalent chromium oxide.

As indicated above, in certain embodiments of this invention, a mixtureof HFC-245cb, HFC-1234yf, HFC-1234ze, HCFC-1233xf, HCFC-1233zd, andHFC-245fa that are present in the product mixtures made according to theprocesses of the invention, is reacted with HF in a liquid-phasefluorination reactor in the presence of a liquid-phase fluorinationcatalyst. The conditions of the fluorination are similar to thosedescribed for the mixture of HFC-1234ze and HFC-245cb above. Thefluorination catalysts for the above liquid-phase embodiments of theinvention may be selected from those described for the liquid-phaseembodiment the chlorofluorination reactor described herein.

The amount of HF required for the liquid-phase reaction is determined bythe total amount of HFC-1234yf, HFC-1234ze, HCFC-1233xf, andHCFC-1233zd, present in the mixture. The mole ratio of HF to the sum ofthe moles of HFC-1234yf, HFC-1234ze, HCFC-1233xf, and E/Z-HCFC-1233zd istypically from about the stoichiometric amount (between 1:1 to 2:1) toabout 100:1, and is preferably from about 8:1 to about 50:1. Suitabletemperatures for these embodiments of the invention are typically withinthe range of from about 30° C. to about 180° C., preferably from about50° C. to about 150° C. The resulting mixture of pentafluoropropanes(i.e., HFC-245cb and HFC-245fa) may be then be freed of HF and recoveredas individual compounds by techniques known to the art.

The reactor, distillation columns, and their associated feed lines,effluent lines, and associated units used in applying the process ofthis invention should be constructed of materials resistant to hydrogenfluoride and hydrogen chloride. Typical materials of construction,well-known to the fluorination art, include stainless steels, inparticular of the austenitic type, the well-known high nickel alloys,such as Monel™ nickel-copper alloys, Hastelloy™ nickel-based alloys and,Inconel™ nickel-chromium alloys, and copper-clad steel.

Without further elaboration, it is believed that one skilled in the artcan, using the description herein, utilize the present invention to itsfullest extent. The following specific embodiments are, therefore, to beconstrued as merely illustrative, and do not constrain the remainder ofthe disclosure in any way whatsoever.

EXAMPLES Preparation of 98% Chromium/2% Cobalt Catalyst

A solution of 784.30 g Cr(NO₃)_(3[)9(H₂O)] (1.96 moles) and 11.64 gCo(NO₃)_(2[)6(H₂O)] (0.040 mole) was prepared in 2000 mL of deionizedwater. The solution was treated dropwise with 950 mL of 7.4M aqueousammonia until the pH reached about 8.5. The slurry was stirred overnightat room temperature and then evaporated to dryness in air at 110-120° C.The dried catalyst was then calcined in air at 400° C. for 24 hoursprior to use.

General Procedure for Product Analysis

The following general procedure is illustrative of the method used foranalyzing the products of fluorination reactions. Part of the totalreactor effluent was sampled on-line for organic product analysis usinga gas chromatograph equipped a mass selective detector (GC/MS). The gaschromatography utilized a 20 ft. (6.1 m) long×⅛ in. (0.32 cm) diametertube containing Krytox® perfluorinated polyether on an inert carbonsupport. The helium flow was 30 mL/min (5.0×10⁻⁷ m³/sec). Gaschromatographic conditions were 60° C. for an initial hold period ofthree minutes followed by temperature programming to 200° C. at a rateof 6° C./minute.

Legend

215aa is CClF₂Cl₂CF₃ 216aa is CF₃CCl₂CF₃ 216ba is CClF₂CClFCF₃ 217ba isCF₃CClFCF₃ 217ca is CClF₂CF₂CF₃ 224aa is CF₃CCl₂CHClF 224ba isCF₃CClFCHCl₂ 225aa is CHF₂Cl₂CF₃ 225ba is CHClFCClFCF₃ 226ba isCF₃CClFCHF₂ 226ca is CF₃CF₂CHClF 226da is CF₃CHClCF₃ 227ca is CF₃CF₂CHF₂233ab is CF₃CCl₂CH₂Cl 235da is CF₃CHClCHF₂ 236fa is CF₃CH₂CF₃ 243db isCF₃CHClCH₂Cl 244db is CF₃CHClCH₂F 245cb is CF₃CF₂CH₃ 245fa is CF₃CH₂CHF₂1223xd is E- and Z-CF₃CCl═CHCl 1233xf is CF₃CCl═CH₂ 1233zd is E- andZ-CHCl═CHCF₃ 1234ze is E- and Z-CHF═CHCF₃ 1234yf is CH₂═CFCF₃ 1243zf isCH₂═CHCF₃

Examples 1-6 Chlorofluorination of CF₃CH═CH₂

The 98% chromium/2% cobalt catalyst prepared above (21.4 g, 15 mL, −12to +20 mesh, (1.68 to 0.84 mm)) was placed in a ⅝″ (1.58 cm) diameterInconel™ nickel alloy reactor tube heated in a fluidized sand bath. Thecatalyst was pre-fluorinated by treatment with HF as follows. Thecatalyst was heated from 45° C. to 175° C. in a flow of nitrogen (50cc/min) over the course of about 1.5 h. HF was then admitted to thereactor at a flow rate of 50 cc/min for 1.3 h at a temperature of 175°C. The reactor nitrogen flow was decreased to 20 cc/min and the HF flowincreased to 80 cc/min; this flow was maintained for 0.3 h. The reactortemperature was then gradually increased to 400° C. over 1 h. After thisperiod, the HF and nitrogen flow was stopped and the reactor brought tothe desired operating temperature. A flow of HF vapor, CF₃CH═CH₂, andCl₂ then started through the reactor. Part of the reactor effluent wasanalyzed by on line GC/MS.

The results of the chlorofluorination of CF₃CH═CH₂ over the 98/2 Cr/Cocatalyst at various operating temperatures and indicated molar ratios ofHF, CF₃CH═CH₂, and Cl₂ are shown in Table 1; analytical data is given inunits of GC area %. The nominal catalyst bed volume was 15 cc; thecontact time (CT) was 15 seconds. Examples 1 and 2 were carried out inthe absence of the catalyst.

TABLE 1 Chlorofluorination of HFC-1243zf HF/1243/Cl₂ Ex. No. Ratio T, °C. 1243zf 243db 244db 1234yf 245cb 1233xf 1 10/1/4 140 3.0 54.2 9.8 5.70 1.4 2^(a) 10/1/1 140 31.3 46.2 11.8 2.8 0 1.5 3^(b) 10/1/1 300 5.9 0 05.9 22.2 30.7 4^(c) 10/1/4 325 0 0 0 0 0 0 5 10/1/1 350 9.1 0 0 11.311.3 25.2 6 10/1/1 375 12.8 0 0 11.6 6.3 20.6 HF/1243/Cl₂ Ex. No. RatioT, ° C. 1233zd 1234ze 245fa 1223xd 233ab 226ba 227ca 1 10/1/4 140 7.7 —— 1.0 6.3 0 0 2^(a) 10/1/1 140 1.4 — — 0 1.3 0 0 3^(b) 10/1/1 300 4.12.1 1.3 20.2 0 0 0 4^(c) 10/1/4 325 0 0 0 0 0 23.8 13.9 5 10/1/1 35012.4 4.7 1.9 18.1 0 0.2 0 6 10/1/1 375 17.6 6.5 2.3 16.1 0 0.2 0^(a)243db and 244db confirmed by ¹H and ¹⁹F NMR. ^(b)245cb and 1233xfconfirmed by ¹H and ¹⁹F NMR. ^(c)Additional major products were 215aa,216aa, 216ba, 225aa, 225ba, 226ca, 226da

The invention claimed is:
 1. A process for making at least one productcompound selected from the group consisting of CF₃CH₂CHF₂, CF₃CH═CHF andCF₃CH═CHCl, comprising: reacting at least one starting material selectedfrom the group consisting of halopropenes of the formula CX₃CH═CH₂ andhalopropenes of the formula CX₂═CHCH₂X wherein each X is independentlyselected from the group consisting of F and Cl, with HF and Cl₂ in areaction zone, optionally in the presence of a chlorofluorinationcatalyst, to produce a product mixture comprising HF, HCl, CF₃CH₂CHF₂,CF₃CH═CHF and CF₃CH═CHCl, wherein the molar ratio of HF to total amountof starting material fed to the reaction zone is at least stoichiometricand wherein the molar ratio of Cl₂ to total amount of starting materialfed to the reaction zone is 2:1 or less; and recovering said at leastone product compound from the product mixture.
 2. The process of claim 1wherein CF₃CH═CHF is recovered.
 3. The process of claim 2 whereinCF₃CH₂CHF₂ from the product mixture is dehydrofluorinated to produceadditional CF₃CH═CHF.
 4. The process of claim 1 wherein CF₃CH═CHCl fromthe product mixture is fluorinated to produce at least one of CF₃CH₂CHF₂and CF₃CH═CHF.
 5. The process of claim 1 wherein CF₃CH₂CHF₂ isrecovered.
 6. The process of claim 1 wherein the product mixture furthercomprises CF₃CF═CH₂; and wherein CF₃CF═CH₂ from the product mixture isrecovered.
 7. The process of claim 1 wherein the product mixture furthercomprises CF₃CF₂CH₃; and wherein a mixture of CF₃CF₂CH₃ and CF₃CH═CHF isrecovered and further reacted with HF in the liquid phase underfluorination conditions in the presence of a fluorination catalyst toproduce a mixture comprising CF₃CH₂CHF₂ and CF₃CF₂CH₃.
 8. The process ofclaim 1 wherein the product mixture further comprises CF₃CF₂CH₃; andwherein a mixture of CF₃CF₂CH₃ and CF₃CH═CHF is recovered and furtherreacted under dehydrofluorination conditions in the presence of adehydrofluorination catalyst to produce a mixture comprising CF₃CH═CHFand CF₃CF═CH₂.
 9. The process of claim 1 wherein CF₃CH₂CHF₂, CF₃CH═CHFand CF₃CH═CHCl from the product mixture together with CF₃CF₂CH₃,CF₃CF═CH₂, and CF₃CCl═CH₂ from the product mixture, if present, arefurther reacted with HF in the liquid phase under fluorinationconditions in the presence of a fluorination catalyst to produce amixture comprising CF₃CH₂CHF₂ and CF₃CF₂CH₃.
 10. The process of claim 9wherein CF₃CH₂CHF₂ and CF₃CF₂CH₃ from the mixture is dehydrofluorinatedto produce both CF₃CH═CHF and CF₃CF═CH₂; and wherein both CF₃CH═CHF andCF₃CF═CH₂ are recovered.
 11. The process of claim 1 wherein the productmixture further comprises CF₃CCl═CH₂; and wherein the CF₃CCl═CH₂,CF₃CH₂CHF₂ and CF₃CH═CHCl from the product mixture are further reactedwith HF in the liquid phase under fluorination conditions in thepresence of a fluorination catalyst to produce a mixture comprisingCF₃CH₂CHF₂ and CF₃CF₂CH₃.
 12. The process of claim 1 wherein thestarting material is reacted in the vapor phase in the presence of achlorofluorination catalyst.
 13. The process of claim 12 wherein thechlorofluorination catalyst comprises at least one chromium-containingcomponent selected from the group consisting of crystallinealpha-chromium oxide where from about 0.05 atom % to about 6 atom % ofthe chromium atoms in the alpha-chromium oxide lattice are replaced bytrivalent cobalt atoms, and crystalline alpha-chromium oxide where fromabout 0.05 atom % to about 6 atom % of the chromium atoms in thealpha-chromium oxide lattice are replaced by trivalent cobalt atomswhich has been treated with a fluorinating agent.